/*
 * This file is part of the TREZOR project, https://trezor.io/
 *
 * Copyright (C) 2017 Saleem Rashid <trezor@saleemrashid.com>
 *
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <unistd.h>

#include <libopencm3/stm32/flash.h>

#include "memory.h"
#include "oled.h"
#include "rng.h"
#include "setup.h"
#include "timer.h"

#define EMULATOR_FLASH_FILE "emulator.img"

uint8_t* emulator_flash_base = NULL;

uint32_t __stack_chk_guard;

static int urandom = -1;

static void setup_urandom(void);
static void setup_flash(void);

void setup(void)
{
    setup_urandom();
    setup_flash();
}

void __attribute__((noreturn)) shutdown(void)
{
    sleep(2);
    exit(0);
}

void emulatorRandom(void* buffer, size_t size)
{
    ssize_t n = read(urandom, buffer, size);
    if (n < 0 || ((size_t)n) != size) {
        perror("Failed to read /dev/urandom");
        exit(1);
    }
}

static void setup_urandom(void)
{
    urandom = open("/dev/urandom", O_RDONLY);
    if (urandom < 0) {
        perror("Failed to open /dev/urandom");
        exit(1);
    }
}

static void setup_flash(void)
{
    int fd = open(EMULATOR_FLASH_FILE, O_RDWR | O_SYNC | O_CREAT, 0644);
    if (fd < 0) {
        perror("Failed to open flash emulation file");
        exit(1);
    }

    off_t length = lseek(fd, 0, SEEK_END);
    if (length < 0) {
        perror("Failed to read length of flash emulation file");
        exit(1);
    }

    emulator_flash_base = mmap(NULL, FLASH_TOTAL_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if (emulator_flash_base == MAP_FAILED) {
        perror("Failed to map flash emulation file");
        exit(1);
    }

    if (length < FLASH_TOTAL_SIZE) {
        if (ftruncate(fd, FLASH_TOTAL_SIZE) != 0) {
            perror("Failed to initialize flash emulation file");
            exit(1);
        }

        /* Initialize the flash */
        flash_erase_all_sectors(FLASH_CR_PROGRAM_X32);
    }
}
